Interesting questions, here's how I look at it... Another way of asking the questions is how many multiples of 2 or 5 are there between 1 and 1000. Well if you look at '2' you can start counting the number of terms that 2 is multiplied by another number and their result is less then 1000. For instance, 2*1=2 (so that is one), 2*2=4 (so that is two), 2*3=6 (so that is three) and so on until you get to 2*500=1000. So any number greater then 500 would be larger than 1000. Now, notice that there would be 500 different numbers you could multiple 2 by up to 1000. So there must be 500 terms that are divisible by 2. We repeat this for 5: 5*1=5 (there is the first), 5*2=10 (there is the second)... 5*200=1000. Using the same method as before, you can conclude there are 200 terms that are divisible by 5. Here is where it gets interesting; it would be easy to just say well 500+200=700 terms. But this would not be correct, because each number can only be counted once so terms like 10, 20, 30 were counted for both 2 and 5. So how many terms were double counted, we fortunately we can use the same method as above realizing that this occurred for all number which are a multiple of the product of 2 and 5--so multiples of 10. How many multiples of 10 are there between 1 and 1000? Well, there are 100. So, how many numbers between 1 and 1000 are divisible by 2 or 5? It should be the number of terms divisible by 2 plus the number of terms divisible by 5 minus the number of duplicate terms. 500+200-100 = 600
How many numbers are divisible by 9 between 5 and 1000²
There are 66 numbers between 1 and 1,000 that are divisible by 15.
There are 267 such numbers.
There are 90 such numbers.
90.
How many numbers are divisible by 9 between 5 and 1000²
There are 66 numbers between 1 and 1,000 that are divisible by 15.
125 (including 1000)
There are 41 numbers between 1 and 1,000 that are divisible by 3 and 8?
There are 466 numbers between 1 and 1,000 that are divisible by three or five.
There are 599 numbers between 1 and 1,000 that are divisible by two or five.
There are 267 such numbers.
There are 90 such numbers.
142 of them.
90.
142 of them.
There are many numbers between 500 and 1000 divisible by 3 and 9. Any number divisible by 9 is divisible by 3. How about 900?